Currently, a variety of fluid delivery devices are available for acquiring and delivering small volumes, i.e. less than 1 mL. These methods include micro-syringes, MEMS devices, pin-style devices, and other known devices. Pin-style devices are commonly used in arrays to perform repeated fluid manipulation steps. Some of the more well-known applications for these pin-style devices include DNA assays, protein sequencing, replicating genome and microbial libraries, and the like. Typical pin-style devices include a metal pin or needle which is specifically designed for delivering a given volume of fluid. Further, these devices are also designed for manipulation of either hydrophobic or hydrophilic fluids. As such, these devices are typically fixed designs such that separate pins are required to change delivery volumes or fluid type. These devices are also often limited in design shape based on available machining techniques; thus, there are limits as to how small the volumes of fluid can be. Further, repeatability of pin shape can vary slightly from one pin to the next. As a result, as fluid volumes decrease, repeatability using an array of such pins can in some cases become a significant problem. Additionally, pin-style devices tend to suffer from a drift in delivery volumes which is related to a change in the surface energy of the pins as a result of interaction with the fluid. Various approaches such as cleaning the pins and statistical methods can help to reduce these difficulties. However, these approaches often entail additional time and expense.
For these and other reasons, the need exists for improved methods and systems which can be used to deliver very small volumes of fluid, which have a high degree of repeatability, increase control and range of delivery volumes, and are convenient to manufacture.